Its scikit-image Download says:
pip install -U scikit-image
or
easy_install -U scikit-image
but both fail
It's generally a bad idea to install libraries on your system-wide Python. Use a virtualenv for each project instead.
First install virtualenv globally on your Mac:
$ [sudo] pip install virtualenv
Then use virtualenv command to create a new (a copy) of Python executable:
$ cd your/prefred/folder
$ virtualenv your_project
Activate the virtualenv:
$ source your_project/bin/activate
Your virtualenv is created and activated (the prompt is changed to show the activation). You can install anything in it:
$ pip install -U scikit-image
pip install scikit-image
pip install --upgrade scikit-image
to call use skimage